Fall 2014 - ‘Lumpless’ Defibrillator Technology

Arrhythmia patients who have traditional implantable cardioverter defibrillators (ICDs) are familiar with “the lump” – the place on their upper chest where the device protrudes under their skin. Now, subcutaneous ICDs eliminate the lump and offer several significant benefits to qualifying patients.

In general, ICD technology is used to control life-threatening arrhythmias (irregular and/or fast heart beats). “There are different kinds of a r rh y thmia s , ” says Dr. Hamrick. “ICDs are used to control the types that cause sudden cardiac arrest or death.”

Sudden cardiac arrest (SCA) occurs when the heart suddenly stops beating. Survival depends on immediate treatment. With ICDs, that immediate treatment comes in the form of an electric shock to the heart, called defibrillation. ICDs also monitor heart rhythm so they can detect an irregularity and provide the appropriate shock to restore normal heart rhythm.

“The invention and implementation of ICD technology has extended and saved countless lives,” notes Dr. Netrebko. Both he and Dr. Hamrick have implanted ICDs in hundreds of patients.

An electrophysiologist (a cardiologist who specializes in heart rhythms) implants the traditional ICD into the patient’s upper chest wall. The cardiologist then inserts the ICD’s leads (wires with electrodes on the ends) into the heart through a vein (transvenously) in the upper chest.

The “s” in the new ICD acronym S-ICD stands for subcutaneous, which means the new ICD is implanted just under the skin on the patient’s side, a few inches below the underarm. “Patients appreciate the absence of the lump in the upper chest, which is characteristic of the traditional ICD,” says Dr. Hamrick. “I don’t even realize I have it,” remarks 81-year-old Robert Wall, who Dr. Hamrick implanted with an S-ICD in February.

Who Is a Good Candidate for an S-ICD?

Though S-ICDs are not recommended for patients with slow heart rates in need of pacing, Dr. Hamrick explains, many patients who have arrhythmias do qualify for them. Candidates for S-ICDs include patients who have:

Structural heart disease (ex. patent foramen ovale)

Veins that are difficult to access

Heart valve issues

Had an infection in their veins in the past

S-ICDs can be a better fit than traditional ICDs for younger patients, who tend to be more physically active than older i n d i v i d u a l s . “Increased levels of mechanical stress associated with physical activity in younger patients represent a risk for lead failure in the conventional ICD system,” says Dr. Netrebko. “The unique lead construction of the subcutaneous ICD is an attractive option for young patients requiring an ICD but not a concomitant pacemaker.”

Dr. Hamrick stresses the importance of diagnosis and treatment of arrhythmias. “More people die of heart rhythm problems than any other type of cardiac condition,” he says.

Do you have a heart rhythm issue? If you don’t know, start with a visit to your primary care doctor to find out.

Important Benefits of S-ICDs

The benefits of S-ICDs are more than skin deep. “Traditional ICDs are implanted into the heart; S-ICDs are not, which is beneficial in several important ways,” explains Dr. Hamrick. These benefits include: